An asterisk is the figure of a star (*) used as a reference mark,
or to indicate omission. (From the Latin asteriscus, little star.
Quid clarius asteriscis?)

An asterick, on the other hand, is nothing at all, but the word
asterick is often used as a synonym for asterisk.

Why? Well, asterick is easier to pronounce. If you drop the
"s" from asterisk, you get asterik. And most people will
know that you mean asterisk when you say asterik, so
intelligibility is not compromised to any significant degree. On the
other hand, if you substitute the word "rik" for "risk", as in
"he's taking a terrible rik", people will think you have a sock in
your mouth.

My first encounter with asterick came 18 years ago
during a conversation with a "systems analyst". At first I
thought that asterick might be computer lingo for "asterisk".
I soon discovered that it was not computer lingo
at all, just weirdness. More troubling were
the same fellow's references to "physical date".
No, he wasn't talking about a recording format, e.g. CCYYMMDD
in a binary integer, or unsigned packed decimal, or EBCDIC or
ASCII characters. When he said "physical date" he really meant
"fiscal date"! Yikes!

On 12/7/97, an AltaVista search for the word "asterisk" yielded
48,022 pages, distributed by domain as shown in the table to the
right. A search for "asterick" yielded 1,172 pages. If publishers
in each domain were equally likely to substitute "asterick" when they
meant "asterisk", we would expect the percentage of asterisk and
asterick usage to be the same for
each domain. But it is not. By dividing the "asterick" percentage
by the asterisk percentage, we compute an Asterick Usage Index.
The chart shows clearly that "asterick" is an American vice.

Five-star asterick sites are:

Alma College, with 39 (wow!) asterick pages. These guys account for 3.3% of all the asterick pages! See Alma's Cognitive Science page for an example.